Look at your watch for just one During that time，The popuiation of the world increased by Perhaps you think that is Hoever，during the next hour，over15540 more babies will be born on the So it goes on，hour after In oneday，people have to produce food fover 370000 more Multiply this justthink how many more there will be in one year!What will happen in a hundred years? The increasing population may be the greatest challenge of the world The world's population is growing faster and Two thousang years ago，there only 250millon people on the At the beining of the20thcentury，the world'spopulation was about In 1990，it reached more than five Now at the beininjg of the 21stcentthe world's population has passed six people say that by the yeay 2010it may be seven That means in about 600 years，there will br standing room only on the Each person will have one half to one square metre of space to live There will be hardly enough space ror angbody It has been estimated that a thousand years ago there were less than 400 million people on However， in the recent thousand years human population has increased nearly 20 Nowadays the world population has reached more than 7000 The population explosion has caused many Generally， they come down to four major First， a lot of people can't get employment， which is a universal problem in the Second， in developing countries there are not enough shelters for too many people and so people are not properly housed and even are exposed to the Third， in underdeveloped countries a lot of people suffer from hunger because of food shortage， which in turn causes many other problems， malnutrition， disease， Fourth， there are not enough schools for so many people and so a lot of people are Therefore， to eliminate these problems， human beings should take effective measures to control
